1. Field of the Invention
The present invention relates to a liquid discharge head for discharging liquid, such as ink, to perform a recording operation onto a recording medium, and more particularly to a method for manufacturing a liquid discharge head performing an ink jet recording.
2. Description of the Related Art
An ink jet recording head has generally been known as one of liquid discharge heads. The structure of the ink jet recording head will briefly be described with reference to FIGS. 12A to 12C.
As illustrated in FIG. 12A, an ink jet recording head 1000 includes a tank holder unit 1500, and a recording element unit 1400 for discharging ink. The ink is guided to the recording element unit 1400 from an ink tank (not illustrated) through an ink supply path formed in the tank holder unit 1500 made of a resin material.
A tank holder 1520 that is formed integral with a part of a wall of the ink supply path illustrated in FIG. 12B and a supply path member 1510 that is formed integral with a part of a wall of the ink supply path illustrated in FIG. 12C are bonded to form an ink supply path 1600 (FIG. 13C).
As a method for forming the ink supply path 1600 by bonding the tank holder 1520 and the supply path member 1510, there has been known a method by a laser welding discussed in Japanese Patent Application Laid-Open No. 2005-096422. The laser welding method is as described below. More specifically, a resin material which has light transmittance to a laser beam and a resin material which has absorptivity to a laser beam are brought into contact with each other. In this state, a laser beam is irradiated to a portion to be welded, so that the resin materials are bonded to each other.
A method for bonding the tank holder 1520 and the supply path member 1510 using the laser welding discussed in Japanese Patent Application Laid-Open No. 2005-096422 will be described with reference to FIGS. 13A and 13B.
Firstly, the tank holder 1520 which has light transmittance to a laser beam and the supply path member 1510 which has absorptivity to a laser beam are brought into contact with each other (FIG. 13A). In this state, a laser beam is irradiated from a laser beam irradiation lens 110 to the tank holder 1520 and the supply path member 1510 (FIG. 13B) to form the ink supply path 1600 (FIG. 13C).
FIG. 13C illustrates an enlarged welded portion in FIG. 13B. In the method for forming the ink supply path by the laser welding, the welded portion 1630 becomes high temperature to fuse the resin. In a welding process, gas G is generated from the welded portion 1630 around the ink supply path 1600 (1600S in FIGS. 12B and 12C) as illustrated in FIG. 13C, so that the gas G might leak to the outside through the ink supply path 1600.
When the gas generated upon the welding reaches the irradiation lens 110 of a laser beam irradiation device 100, the irradiation lens 110 is contaminated which might reduce an irradiation amount of the laser beam.